Pin coupling based thermoelectric device

ABSTRACT

A method includes coupling a number of sets of N and P thermoelectric legs to a substrate. Each set includes an N thermoelectric leg and a P thermoelectric leg electrically contacting each other through a conductive material on the substrate. The method also includes forming a conductive thin film on another substrate, and coupling the each set on an end thereof away from the substrate to the conductive thin film formed on the another substrate through a pin several times longer than a height of the N thermoelectric leg and the P thermoelectric leg of the each set to form a thermoelectric device.

FIELD OF TECHNOLOGY

This disclosure relates generally to thermoelectric devices and, more particularly, to a pin coupling based thermoelectric device.

BACKGROUND

A thermoelectric device may be formed from alternating N and P elements/legs made of semiconducting material on a rigid substrate (e.g., alumina) joined on a top thereof to another rigid substrate/plate (e.g., again, alumina). However, a traditional implementation of the thermoelectric device may be limited in application thereof because of rigidity, bulkiness, size and high costs (>$20/watt) associated therewith.

SUMMARY

Disclosed are a method, a device and/or a system of a pin coupling based thermoelectric device.

In one aspect, a method includes coupling a number of sets of N and P thermoelectric legs on a substrate. Each set includes an N thermoelectric leg and a P thermoelectric leg electrically contacting each other through a conductive material on the substrate. The method also includes forming a conductive thin film on another substrate, and coupling the each set on an end thereof away from the substrate to the conductive thin film formed on the another substrate through a pin several times longer than a height of the N thermoelectric leg and the P thermoelectric leg of the each set to form a thermoelectric device.

In another aspect, a thermoelectric device includes a substrate, and a number of sets of N and P thermoelectric legs coupled to the substrate. Each set includes an N thermoelectric leg and a P thermoelectric leg electrically contacting each other through a conductive material on the substrate. The thermoelectric device also includes another substrate, a conductive thin film formed on the another substrate, and a number of pins corresponding to the number of sets of N and P thermoelectric legs. Each pin couples the each set on an end thereof away from the substrate to the conductive thin film formed on the another substrate. The each pin is several times longer than a height of the N thermoelectric leg and the P thermoelectric leg of the each set.

In yet another aspect, a hybrid solar device includes a solar device element and a thermoelectric device coupled to the solar device element. The thermoelectric device includes a substrate, and a number of sets of N and P thermoelectric legs coupled to the substrate. Each set includes an N thermoelectric leg and a P thermoelectric leg electrically contacting each other through a conductive material on the substrate. The thermoelectric device also includes another substrate, a conductive thin film formed on the another substrate, and a number of pins corresponding to the number of sets of N and P thermoelectric legs. Each pin couples the each set on an end thereof away from the substrate to the conductive thin film formed on the another substrate. The each pin is several times longer than a height of the N thermoelectric leg and the P thermoelectric leg of the each set.

The methods and systems disclosed herein may be implemented in any means for achieving various desired aspects of thermoelectric devices disclosed herein for applications including but not limited to wearable devices, automotive devices and/or components, solar devices and Internet of Things (IoT).

Other features will be apparent from the accompanying drawings and from the detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of this invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

FIG. 1 is a schematic view of a thermoelectric device.

FIG. 2 is a schematic view of an example thermoelectric device with alternating P and N elements.

FIG. 3 is a top schematic view of a thermoelectric device component, according to one or more embodiments.

FIG. 4 is a front schematic view of a thermoelectric device including the thermoelectric device component of FIG. 3, according to one or more embodiments.

FIG. 5 is a schematic view of a solar panel device configured to have the thermoelectric device of FIG. 4 integrated therein.

FIG. 6 is a circuit diagram representation of a hybrid device including the solar panel device of FIG. 5 and the thermoelectric device of FIG. 4 integrated therein.

FIG. 7 is a schematic view of a flat plate collector, according to one or more embodiments.

FIG. 8 is a process flow diagram detailing the operations involved in realizing the thermoelectric device of FIG. 4, according to one or more embodiments.

Other features of the present embodiments will be apparent from the accompanying drawings and from the detailed description that follows.

DETAILED DESCRIPTION

Example embodiments, as described below, may be used to provide a method, a device and/or a system of a pin coupling based thermoelectric device. Although the present embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the various embodiments.

FIG. 1 shows a thermoelectric device 100. Thermoelectric device 100 may include different metals, metal 1 102 and metal 2 104, forming a closed circuit. Here, a temperature difference between junctions of said dissimilar metals leads to energy levels of electrons therein shifted in a dissimilar manner. This results in a potential/voltage difference between the warmer (e.g., warmer junction 106) of the junctions and the colder (e.g., colder junction 108) of the junctions. The aforementioned conversion of heat into electricity at junctions of dissimilar metals is known as Seebeck effect.

The most common thermoelectric devices in the market may utilize alternative P and N type legs/pellets/elements made of semiconducting materials. As heat is applied to one end of a thermoelectric device based on P and N type elements, charge carriers thereof may be released into the conduction band. Electron (charge carrier) flow in the N type element may contribute to a current flowing from the end (hot end) where the heat is applied to the other end (cold end). Hole (charge carrier) flow in the P type element may contribute to a current flowing from the other end (cold end) to the end (hot end) where the heat is applied. Here, heat may be removed from the cold end to prevent equalization of charge carrier distribution in the semiconductor materials due to migration thereof.

In order to generate voltage at a meaningful level to facilitate one or more application(s), typical thermoelectric devices may utilize alternating P and N type elements (legs/pellets) electrically coupled in series (and thermally coupled in parallel) with one another, as shown in FIG. 2. FIG. 2 shows an example thermoelectric device 200 including three alternating P and N type elements 202 ₁₋₃. The hot end (e.g., hot end 204) where heat is applied and the cold end (e.g., cold end 206) are also shown in FIG. 2.

Typical thermoelectric devices (e.g., thermoelectric device 200) may be limited in application thereof because of rigidity, bulkiness and high costs (>$20/watt) associated therewith. Also, these devices may operate at high temperatures using active cooling. Exemplary embodiments discussed herein provide for a thermoelectric platform (e.g., enabled via roll-to-roll sputtering on a substrate (e.g., plastic)) that offers a large scale, commercially viable, high performance, easy integration and inexpensive (<20 cents/watt) route to flexible thermoelectrics.

In accordance with the exemplary embodiments, P and N thermoelectric legs may be deposited on a flexible substrate (e.g., plastic) using a roll-to-roll process that offers scalability and cost savings associated with the N and P materials. In a typical solution, bulk legs may have a height in millimeters (mm) and an area in mm². In contrast, N and P bulk legs described in the exemplary embodiments discussed herein may have a height in microns (μm) and an area in the μm² to mm² range.

FIG. 3 shows a top view of a thermoelectric device component 300, according to one or more embodiments. Here, in one or more embodiments, a number of sets of N and P legs (e.g., sets 302 _(1-M) including N legs 304 _(1-M) and P legs 306 _(1-M) therein) may be deposited on a substrate 350 (e.g., plastic) using a roll-to-roll process discussed above. FIG. 3 also shows a conductive material 308 _(1-M) contacting both a set 302 _(1-M) and substrate 350, according to one or more embodiments; an N leg 304 _(1-M) and a P leg 306 _(1-M) of a set 302 _(1-M) electrically contact each other through conductive material 308 _(1-M).

FIG. 4 shows a front view of thermoelectric device 400 including thermoelectric device component 300, according to one or more embodiments. Here, in one or more embodiments, a pin 402 _(1-M) several times longer than the height of each of the N legs 304 _(1-M) and P legs 306 _(1-M) may couple an N leg 304 _(1-M) and a P leg 306 _(1-M) within a set 302 _(1-M) on an end of the set 302 _(1-M) away from substrate 350 to a conductive thin film 404. In one or more embodiments, conductive thin film 404 may be formed on another substrate 450 (e.g., plastic, same substrate as substrate 350, a substrate (e.g., flexible, rigid) different from substrate 350).

In other words, in one or more embodiments, the sets 302 _(1-M) may be sandwiched between substrate 350 and substrate 450 by way of conductive material 308 _(1-M), pins 402 _(1-M) and conductive thin film 404. In one example embodiment, conductive thin film 404 may be formed on substrate 450 through sputtering. Other ways of forming conductive thin film 404 on substrate 450 are within the scope of the exemplary embodiments discussed herein. Also, it should be noted that the sets 302 _(1-M) may, alternately, be attached/coupled to a rigid substrate such as substrate 350 instead of being sputtered onto a flexible substrate such as substrate 350. In other words, substrate 350 may be a rigid substrate or a flexible substrate.

In one or more embodiments, pins 402 _(1-M) may be pogo pins commonly used in probe cards in the semiconductor industry for testing wafers. Pogo pins are well known to one skilled in the art; therefore, detailed discussed associated therewith has been skipped for the sake of convenience. In one or more embodiments, FIG. 3 shows terminals (370, 372) to measure the potential difference generated based on heat (or, cold) applied at an end of thermoelectric device 400. It is obvious that heat (or, cold) may be applied at any end of thermoelectric device 400; in other words, the heat (or, the cold) may be applied at an end of substrate 350 or substrate 450.

In one or more embodiments, a thermoelectric module (e.g., thermoelectric device 400) with the pin setup may offer several advantages over a traditional implementation. In one or more embodiments, a temperature difference across the thermoelectric P and N legs may be controlled by varying a height, a thickness and/or an area of pins 402 _(1-M) (each of pins 402 _(1-M) whose height, thickness and/or area can be varied may be used). The modularized approach to thermoelectric device 400 may provide for replacing pins 402 _(1-M) with another set thereof having a different height of constituent individual pins, a different thickness of constituent individual pins and/or a different area of constituent individual pins. In one example implementation, the height of each pin 402 _(1-M) may be adjusted through a spring associated therewith.

In one or more embodiments, the controllability of the height, the thickness and/or the area of pins 402 _(1-M) may allow thermoelectric device 400/module to operate at higher temperatures and a wider temperature spectrum compared to a traditional implementation thereof. In the traditional implementation, the height of the P and N legs may be fixed based on material costs and performance. Exemplary embodiments discussed herein may offer scalability and cost savings.

Exemplary embodiments discussed herein (e.g., thermoelectric device 400) may also offer easy integration with respect to solar and solar thermal applications. As discussed above, the traditional thermoelectric module may have a size limitation and may not scale to a larger area. For example, a typical solar panel may have an area in the square meter (m²) range and the traditional thermoelectric module may have an area in the square inch range. A thermoelectric module in accordance with the exemplary embodiments may be of varying sizes and/or dimensions ranging from a few mm² to a few m².

For efficient harnessing of solar energy, optimum hybridization of photovoltaic (PV) and thermoelectric devices may be considered ideal. In the PV operation, ˜40% of solar spectral irradiance may spontaneously be transformed into heat by thermalization loss of high energy photons and transmission loss of low energy photons. Therefore, additional energy harvesting from waste heat may be useful not only for increasing efficiency but also for removing unwanted heat that prevents efficient PV operation. Achieving lossless coupling may enable the power output from the hybrid device be equal to the sum of the maximum power outputs produced separately from individual PV and thermoelectric devices.

FIG. 5 shows a solar panel device 500. Solar panel device 500 may include a glass sheet 502 (e.g., tempered low iron glass) under which a layer of interconnected solar cells 504 may be sandwiched between lamination layers (506, 508). In one implementation, the lamination layers (506, 508) may be made of ethyl vinyl acetate (EVA) films. The framework for solar panel device 500 may be provided by a backsheet 510, which lies underneath lamination layer 508. It should be noted that other implementations of solar panel device 500 are within the scope of the exemplary embodiments discussed herein.

In one or more embodiments, a thermoelectric module 550 (e.g., thermoelectric device 400) may be coupled to the layer of interconnected solar cells 504 between said layer of interconnected solar cells 504 and lamination layer 508 to realize the hybrid device discussed above. FIG. 6 shows a circuit diagram representation of a hybrid device 600 (e.g., solar panel device 500 with thermoelectric module 550 of FIG. 5), according to one or more embodiments. In one or more embodiments, solar panel device 500 may be represented as a current source 602 in parallel with a diode 604 and a shunt resistance R_(SH) 606. In one or more embodiments, the series resistance representation of solar panel device 500 is shown as R_(S) 608 in FIG. 6. In one or more embodiments, thermoelectric module 550 may be represented by a voltage source 612 in series with an internal resistance R_(I) 614. FIG. 6 also shows that the output voltage of hybrid device 600 to be the sum of the voltage of solar panel device 500 (V_(SOLAR)) and the voltage of thermoelectric module 550 (V_(TM)).

Solar thermal collectors may be of several types including but not limited to flat plate collectors, evacuated tube collectors, Integral Collector Storage (ICS) system based collectors, thermosiphon based collectors and concentrating collectors. The most common type of solar thermal collectors may be flat plate collectors. FIG. 7 shows a flat plate collector 700, according to one or more embodiments. In one or more embodiments, flat plate collector 700 may include a glass plate 702 (e.g., tempered glass) on top and an absorber plate 704 (e.g., copper based, aluminum based) on a bottom thereof. Sunlight may pass through glass plate 702 and heat up absorber plate 704; solar energy may thereby be converted into heat energy. The heat may be passed onto liquid passing through pipes 706 attached to absorber plate 704.

The working of a typical flat plate collector is well known to one skilled in the art. Detailed discussion associated therewith has, therefore, been skipped for the sake of convenience. FIG. 7 shows insulation 708, header 710, inlet 712 and outlet 714 of flat plate collector 700 merely for the sake of completeness. It should be noted that glass plate 702 may, instead, be replaced with a polymer cover plate. Other implementations of flat plate collector 700 are within the scope of the exemplary embodiments discussed herein.

In one or more embodiments, a thermoelectric module 750 (e.g., thermoelectric device 400; analogous to thermoelectric module 550) may be integrated into flat plate collector 700 (an example solar thermal collector) at the back of absorber plate 704 (or underneath absorber plate 704). In one or more embodiments, in the case of a pure water heater system implementation, flat plate collector 700 including thermoelectric module 750 may produce electricity in addition to thermal energy to be used for lighting and other purposes; said thermal energy may also heat water at the same time. As absorber plate 704 reaches temperatures in the vicinity of 400 degrees Celsius. (C.), there may be a lot of temperature gradients to be exploited and harvested through thermoelectric module 750.

FIG. 8 shows a process flow diagram detailing the operations involved in realizing a pin coupling based thermoelectric device (e.g., thermoelectric device 400), according to one or more embodiments. In one or more embodiments, operation 802 may involve coupling a number of sets (e.g., sets 302 _(1-M)) of N (e.g., N legs 304 _(1-M)) and P (e.g., P legs 306 _(1-M)) thermoelectric legs on a substrate (e.g., substrate 350). In one or more embodiments, the each set may include an N thermoelectric leg and a P thermoelectric leg electrically contacting each other through a conductive material (e.g., conductive material 308 _(1-M)) on the substrate.

In one or more embodiments, operation 804 may involve forming a conductive thin film (e.g., conductive thin film 404) on another substrate (e.g., substrate 450). In one or more embodiments, operation 806 may then involve coupling the each set on an end thereof away from the substrate to the conductive thin film formed on the another substrate through a pin (e.g., pin 402 _(1-M)) several times longer than a height of the N thermoelectric leg and the P thermoelectric leg of the each set to form/realize the thermoelectric device (e.g., thermoelectric device 400).

It should be noted that the exemplary embodiments discussed above do not limit application thereof to solar devices (e.g., hybrid solar device 600, flat plate collector 700). For example, in low temperature applications such as harvesting body heat in a wearable device, a milli-volt (mV) output of thermoelectric device 400 may be boosted using a Direct Current (DC)-DC converter to a desired voltage output (e.g., 3.3 V) to augment a life of a battery used or to replace said battery. Also, it should be noted that additional electronics and/or wiring may be needed to integrate thermoelectric device 400 within a device/system associated with relevant applications (e.g., automotive devices/components, Internet of Things (IoT).

Although the present embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the various embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. 

What is claimed is:
 1. A method comprising: coupling a plurality of sets of N and P thermoelectric legs to a substrate, each set comprising an N thermoelectric leg and a P thermoelectric leg electrically contacting each other through a conductive material on the substrate; forming a conductive thin film on another substrate; and coupling the each set on an end thereof away from the substrate to the conductive thin film formed on the another substrate through a pin several times longer than a height of the N thermoelectric leg and the P thermoelectric leg of the each set to form a thermoelectric device.
 2. The method of claim 1, comprising at least one of: depositing the plurality of sets of N and P thermoelectric legs on the substrate through a roll-to-roll sputtering process; and forming the conductive thin film on the another substrate through sputtering.
 3. The method of claim 1, wherein at least one of: the pin is a pogo pin, and at least one of: the substrate and the another substrate is one of: a flexible substrate and a rigid substrate.
 4. The method of claim 1, further comprising applying one of: heat and cold to the formed thermoelectric device at an end of one of: the substrate and the another substrate.
 5. The method of claim 4, further comprising controlling a temperature difference across the N thermoelectric leg and the P thermoelectric leg of the each set based on at least one of: varying a height of the pin, a thickness of the pin and replacing the pin with a pin having a different area therefrom.
 6. The method of claim 1, further comprising coupling the formed thermoelectric device to one of: a solar panel device and a solar thermal collector.
 7. The method of claim 4, further comprising forming a set of terminals on the substrate to measure potential difference generated based on the application of the one of: the heat and the cold to the formed thermoelectric device.
 8. A thermoelectric device comprising: a substrate; a plurality of sets of N and P thermoelectric legs coupled to the substrate, each set comprising an N thermoelectric leg and a P thermoelectric leg electrically contacting each other through a conductive material on the substrate; another substrate; a conductive thin film formed on the another substrate; and a plurality of pins corresponding to the plurality of sets of N and P thermoelectric legs, each pin coupling the each set on an end thereof away from the substrate to the conductive thin film formed on the another substrate, and the each pin being several times longer than a height of the N thermoelectric leg and the P thermoelectric leg of the each set.
 9. The thermoelectric device of claim 8, wherein at least one of: the plurality of sets of N and P thermoelectric legs is deposited on the substrate through a roll-to-roll sputtering process, and the conductive thin film is formed on the another substrate through sputtering.
 10. The thermoelectric device of claim 8, wherein at least one of: the each pin is a pogo pin, and at least one of: the substrate and the another substrate is one of: a flexible substrate and a rigid substrate.
 11. The thermoelectric device of claim 8, wherein one of: heat and cold is configured to be applied at an end of one of: the substrate and the another substrate.
 12. The thermoelectric device of claim 11, wherein one of: a height of the each pin is variable, a thickness of the each pin is variable, and the each pin is configured to be replaced with a pin having a different area therefrom to control a temperature difference across the N thermoelectric leg and the P thermoelectric leg of the each set.
 13. The thermoelectric device of claim 11, further comprising a set of terminals formed on the substrate to measure potential difference generated based on the application of the one of: the heat and the cold to the end of the one of: the substrate and the another substrate.
 14. A hybrid solar device comprising: a solar device element; and a thermoelectric device coupled to the solar device element, the thermoelectric device comprising: a substrate; a plurality of sets of N and P thermoelectric legs coupled to the substrate, each set comprising an N thermoelectric leg and a P thermoelectric leg electrically contacting each other through a conductive material on the substrate; another substrate; a conductive thin film formed on the another substrate; and a plurality of pins corresponding to the plurality of sets of N and P thermoelectric legs, each pin coupling the each set on an end thereof away from the substrate to the conductive thin film formed on the another substrate, and the each pin being several times longer than a height of the N thermoelectric leg and the P thermoelectric leg of the each set.
 15. The hybrid solar device of claim 14, wherein the solar device element is an element of one of: a solar panel device and a solar thermal collector.
 16. The hybrid solar device of claim 14, wherein at least one of: the plurality of sets of N and P thermoelectric legs is deposited on the substrate through a roll-to-roll sputtering process, and the conductive thin film of the thermoelectric device is formed on the another substrate thereof through sputtering.
 17. The hybrid solar device of claim 14, wherein at least one of: the each pin of the thermoelectric device is a pogo pin, and at least one of: the substrate and the another substrate of the thermoelectric device is one of: a flexible substrate and a rigid substrate.
 18. The hybrid solar device of claim 14, wherein one of: heat and cold is configured to be applied at an end of one of: the substrate and the another substrate of the thermoelectric device.
 19. The hybrid solar device of claim 18, wherein one of: a height of the each pin of the thermoelectric device is variable, a thickness of the each pin of the thermoelectric device is variable, and the each pin of the thermoelectric device is configured to be replaced with a pin having a different area therefrom to control a temperature difference across the N thermoelectric leg and the P thermoelectric leg of the each set of the thermoelectric device.
 20. The hybrid solar device of claim 18, wherein the thermoelectric device further comprises a set of terminals formed on the substrate to measure potential difference generated based on the application of the one of: the heat and the cold to the end of the one of: the substrate and the another substrate of the thermoelectric device. 